Progressive release jettison tank



April 1951 J. E. REDFORD 2,550,380

PROGRESSIVE RELEASE JETTISQN TANK Filed April 16, 1947 2 Sheets-Sheet 1 INVENTOR JOHN E. REDFORD April 24, 1951 J. E. REDFORD 2,

PROGRESSIVE RELEASE JETTISON TANK Filed April 16. 1947 2 Sheets-Sheet 2 I INVENTOR JOHN E. REDFORD UNITED STATES TENT GFFICE PROGRESSIVE RELEASE JETTISON TANK John E. Redford, Glendale, Caliii, assignor to Lockheed Aircraft Corporation, Burbank, California Application April 16, 1947, Serial No. 741,809

4 Claims. 1

This invention relates to the progressive release of jettisonable equipment such as auxiliary fuel tanks, suspended from the wings of airplanes, and releasable therefrom in flight when empty or in the event of emergency.

Jettisonable fuel tanks have been used for some time because of the added range provided thereby and the fact that the use of such auxiliary tanks suspended from the wings outboard of the ment of the equipment prior to complete release thereof.

Other objects and features of this invention will be readily understood. from the following detailed description of a typical preferred form of the invention wherein reference will be made to the accompanying drawings.

This invention is shown in a preferred form in connection with jettisonable fuel tanks attached adjacent the wing tips of an airplane.

In the drawings:

Figure 1 is a plan view of an airplane equipped with fuel tanks mounted in the manner of this invention;

landing gear actually reduce the aerodynamic Figure 2 is an enlarged section on the line stresses imposed on the wing structure as com- 2-2 of Figure 3 showing the progressive release pared to installing an equivalent weight within mechanism attaching the tank to the wing; the fuselage of the airplane. In practice, how- Figure 3 is a section on the line 33 of Figure ever, the release of such tanks in flight has re- 2 showing the delayed release mechanism; sulted in various accidents which have forced Figure 4 is a section on the line 4-4 of Figure the imposition of restrictions as to airplane speed 2 showing the initial release mechanism; and and altitude at the moment of release. For ex- Figure 5 is a section similar to Figure 2 whereample, if the tank is released at high speed, in the tanllc1 is shown as pivoted into the position especially when empty, the aerodynamic forces at which t e delayed release mechanism is an oacting on the streamlined tank at the moment of matically tripped. release may cause its nose to swing up and hit As shown in the drawings: the wing and/or aileron, or the empennage sur- An airplane [0, with wings II, is provided with faces of the airplane. Such restrictions on the jettisonable fuel tanks |2 carried suspended be- I3 f he in s, outb rd of the f iji ci'e a se d si z s a in d ia gz it i fv iii il -2J2 a i lzz n l lf 'uel is :withgrai vn fron the tanks vate these difficulties and increase the damage l2 by means of a conduit l5 leading to the ento the airplane in the event of accidental con gine fuel system (not shown) which conduit'has tact. a slip joint or quick discomtefit tiling? {a2 delfiiligariy It is, accordingly, an object of this invention pipe I! extending down in o e a ie to provide means to facilitate the release or jetit is desirable to use one of the self-sealing quick tisoning of tanks or external compartments susdisconnect fittings commercially available, a pended from the wing or other airplane structure simple rubber sleeve will serve the present purand to control their initial movement prior to pose, as it can be arranged to slip off the pipe complete detachment and free flight relative to I! when the tank is released. the airplane. The principal object of this in- Jettisonable fuel tanks have heretofore been verition is to impose a rotational force on the obd iuspended by akconientiongl shackle, arl lalajgoilizs jec about an axis parallel to the line of flight o a bomb shac le, ispose axially of e an in order to produce a spin or rotational inertia In my invention, two parallel lines of support are therein to oppose aerodynamic forces thereon provided, spaced on either side of a vertical plane having a tendency to cause the object to nose through the tank axis, thus eliminating the need up or tumble end over end at the moment of of sway braces for the tank. Each line of support comprises two hooks spaced on a fore and l n biect f hls i ven i n to p aft line, the outboard pair of hooks l8 in Figure v e p v {m f r l a ab y pp r 2 engaging eyes is on the tank and being arieltltisonagle equipment from aircraft structures ranged fo initial pivotalemovement of the tank w erein he Weight of the equipment is normally upon the release of an inboard pair of hooks 20 supported or distributedover a plurality of points, engaging eyes 2| on the tank and release of the equlpment arranged The hooks 20 are shown in Figure 4 as part of gresslvely regards 9 Pants Support conventional bomb shackle 22 which can be re- Whereby to Impose deslred an'ectlonal move leased by the pilot as by an electrical solenoid 23. When so released the tank swings down about the hooks [8 as pivots, pulling the fuel slip joint l6 free and withdrawing a lug 24 from looking engagement with a cam 25 (see Figure 3). The cam is pivoted at 26 and has links 21 connecting the levers 28 on shafts 29 carrying the hooks l8 previously mentioned. As th shackle 22 releases a predetermined time in advance of the disengagement of the lug 24 from the cam 25, so that the entire weight of the tank is then suspended from the hooks l8 and serves to rotate the hooks l8 and shafts 29 into disengagement with the eyes I9. The extent of rotation of the tank prior to final release of the hooks l8 can be predetermined by the spacing or position of. the cam 25 and lug 24 relative to the hooks [8, as well as the initial overlap or interference between the cam and lug.

The controlled initial downward and outward movement of the tank, with its axis restrained or maintained generally parallel to that of the flight path of the airplane, imparts a rotary motion or spin to the tank that stabilizes its initial flight, preventing tumbling or end-over-end motion at themoment of final release.

It will thus be seen that I have invented an improved sequential or progressive release for jettisonable tanks and the like which eliminates the need of sway braces and imposes a predetermined initial flight path on the tank at the moment of final release by imparting a spin or rotational inertia thereto to resist aerodynamic forces acting on the tank and having a tendency to produce tumbling thereof at the instant of release.

Having thus described my invention and the present preferred embodiments thereof, I desire to emphasize the fact that many modifications may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim as my invention:

1. A progressive release mechanism adapted to impart axial rotation in a streamlined jettisonable tank and the like, comprising transversely spaced separately releasable inboard and outboard supporting means for said tank, means for releasing the inboard supporting means at the will of the pilot, and means for automatically releasing the outboard supporting means after a predetermined pivotal movement of said tank about said last mentioned supporting means comprising a cam associated with said outboard supporting means and a blocking lug carried by said tank and arranged to block said cam during the predetermined pivotal movement of said tank.

2. A progressive release mechanism adapted to impart axial rotation in an elongated jettisonable tank and the like, comprising a pair of transversely spaced separately releasable supporting means for said tank, means for releasing one of mi llitll wwmw said spaced supporting means at the will of the pilot, and means for automatically releasing the other of said spaced supporting means after a predetermined pivotal movement of said tank about said last mentioned supporting means comprising a detent associated with the other supporting means and a lug carried by said tank in a position to normally block said detent and to release the same after a predetermined pivotal movement of said tank.

' 3. A progressive release mechanism adapted to initiate rotary motion in a jettisonable tank and the like, comprising transversely spaced releasable inboard and outboard supporting means for said tank, means for releasing the inboard supporting means at the will of the pilot, and means for automatically releasing the outboard supporting means, said releasing means including latch means associated with said last mentioned supporting means, said latch means being so arranged as to be mechanically released by the tank after a predetermined pivotal movement of said tank about said -last mentioned supporting means.

4. A progressive release mechanism for initiating axial rotation in jettisonable objects of circular section suspended externally from an airplane, comprising separate pairs of longitudinally aligned couplings, one pair of couplings being disposed on either side Of the center of gravity of the object suspended thereby, means for releasing one pair of couplings at the will of the pilot, and means for sequentially releasing the other pair of couplings, said last mentioned means including a mechanical latch associated with said last mentioned couplings and released by a predetermined axial rotation of the object to be jettisoned.

JOHN E. REDFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 1,322,160 Breguet Nov. 18, 1919 2,010,817 Henry Aug. 13, 1935' 2,124,867 Akerman July 26, 1938 2,416,104 Lerche Feb. 18, 1947 2,421,699 Johnson June 3, 1947 FOREIGN PATENTS Number Country Date 80,178 Austria Feb, 25, 1920 amwmwwwn. 

